Information in abundance on dentistry-and-orthodontics--simple and clear section-by-section, though not as logically ordered as it might be. Because the majority of ""tooth disharmonies"" arise after conception (i.e., are not inherited), the emphasis here is on prevention: oral hygiene, good posture, good nutritional habits will all contribute to straight teeth. From infancy to adulthood, Holt discusses how to develop good habits, how to counteract harmful ones, and what is entailed in formal corrective treatment. His discussion of controversial matters is up-to-date (extractions are now generally frowned on because they can contribute to the development of gum disease and thus lead to further tooth loss); and considerable help is given on special efforts needed for oral hygiene while receiving orthodontic treatment. If readers can overlook an occasionally pompous air (""When the parent or patient is visiting the orthodontist, certain standards of conduct will be appreciated""), they can learn much of specific benefit. General information about dental care, however, is presented better elsewhere (most recently in Goldberg, Your Mouth Is Your Business).